Chemical calcium indicators.
Our understanding of the underlying mechanisms of Ca2+ signaling as well as our appreciation for its ubiquitous role in cellular processes has been rapidly advanced, in large part, due to the development of fluorescent Ca2+ indicators. In this chapter, we discuss some of the most common chemical Ca2+ indicators that are widely used for the investigation of intracellular Ca2+ signaling. Advantages, limitations and relevant procedures will be presented for each dye including their spectral qualities, dissociation constants, chemical forms, loading methods and equipment for optimal imaging. Chemical indicators now available allow for intracellular Ca2+ detection over a very large range (<50 nM to >50 microM). High affinity indicators can be used to quantify Ca2+ levels in the cytosol while lower affinity indicators can be optimized for measuring Ca2+ in subcellular compartments with higher concentrations. Indicators can be classified into either single wavelength or ratiometric dyes. Both classes require specific lasers, filters, and/or detection methods that are dependent upon their spectral properties and both classes have advantages and limitations. Single wavelength indicators are generally very bright and optimal for Ca2+ detection when more than one fluorophore is being imaged. Ratiometric indicators can be calibrated very precisely and they minimize the most common problems associated with chemical Ca2+ indicators including uneven dye loading, leakage, photobleaching, and changes in cell volume. Recent technical advances that permit in vivo Ca2+ measurements will also be discussed.
Paredes
R Madelaine
RM
Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
Etzler
Julie C
JC
Watts
Lora Talley
LT
Zheng
Wei
W
Lechleiter
James D
JD
D000758:Anesthesia / Q000379:methods / Q000662:veterinary; D000814:Aniline Compounds / Q000737:chemistry; D000818:Animals; D001253:Astrocytes / Q000502:physiology; D001572:Benzofurans / Q000737:chemistry; D002118:Calcium / Q000032:analysis / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002451:Cell Compartmentation; D003600:Cytosol / Q000378:metabolism; D005452:Fluoresceins / Q000737:chemistry; D005456:Fluorescent Dyes / Q000032:analysis / Q000737:chemistry; D016257:Fura-2 / Q000031:analogs & derivatives / Q000737:chemistry; D005998:Glycine / Q000031:analogs & derivatives / Q000737:chemistry; D006575:Heterocyclic Compounds, 3-Ring / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry; D007202:Indicators and Reagents / Q000494:pharmacology; D007211:Indoles / Q000737:chemistry; D051379:Mice; D009930:Organic Chemicals / Q000737:chemistry; D010296:Parietal Lobe / Q000502:physiology; D014966:Xanthenes / Q000737:chemistry
D000814:Aniline Compounds; D001572:Benzofurans; C409648:Fluo 4; D005452:Fluoresceins; D005456:Fluorescent Dyes; D006575:Heterocyclic Compounds, 3-Ring; D007093:Imidazoles; D007202:Indicators and Reagents; D007211:Indoles; C503942:Oregon green 488 BAPTA-1; D009930:Organic Chemicals; D014966:Xanthenes; C068483:rhod-2; C058776:2-(2-(5-carboxy)oxazole)-5-hydroxy-6-aminobenzofuran-N,N,O-triacetic acid; C071336:calcium green; C082877:fura red; C453498:magnesium green; C059715:Fluo-3; C048960:indo-1; D002118:Calcium; D005998:Glycine; D016257:Fura-2